package cap.action;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Random;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class IdentityServlet extends HttpServlet {

    public static final char[] chars={'2','3','4','5','6','7','8','9','A'};
    public static Random random=new Random();

    public static String getRandomString(){
        StringBuffer buffer=new StringBuffer();
        for(int i=0;i<6;i++){
            buffer.append(chars[random.nextInt(chars.length)]);
        }
        return buffer.toString();
    }
    public static Color getRandomColor(){
        return new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255));
    }
    public static Color getReverseColor(Color c){
        return new Color(255 - c.getRed(), 255 - c.getGreen(), 255 - c.getBlue());
    }
    public IdentityServlet() {
        super();
    }
    public void destroy() {
        super.destroy();
    }
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("image/jpeg");
        String randomString = getRandomString();
        request.getSession(true).setAttribute("randomString", randomString);
        int width=100;
        int height=30;
        Color color=getRandomColor();
        Color reverse=getReverseColor(color);
        //画出验证码图像
        BufferedImage bi=new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g=bi.createGraphics();
        g.setFont(new Font(Font.SANS_SERIF,Font.BOLD,16));
        g.setColor(color);
        g.fillRect(0, 0, width, height);
        g.setColor(reverse);
        g.drawString(randomString, 18, 20);
        for(int i=0,n=random.nextInt(100);i<n;i++){
            g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);
        }
        ServletOutputStream out= response.getOutputStream();
        JPEGImageEncoder encoder=JPEGCodec.createJPEGEncoder(out);
        encoder.encode(bi);
        out.flush();
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request,response);
    }
    public void init() throws ServletException {
    }
}
